Three sub-projects will examine determinants of growth and nutritional status of children with sickle cell disease (SCD). These include: 1) a longitudinal study of growth,body composition and dietary intake; 2) a study of resting and total energy expenditure (EE) of children with SCD in a usual state of health compared normal controls; and 3) a study of resting EE and dietary intake of children during acute SCD complications.